A number of methods and apparatuses exist for generating arrays and other patterns of biological material upon a surface. Some advantages of such methods and apparatuses (and of microarray technology in general) include increased throughput afforded by parallel processing and reductions in the amounts of materials and labor required for sample processing, which can result in increased productivity and reductions in costs. Existing apparatuses and methods for deposition of various materials at small scales (e.g., on the scale of tens of microns) have had mixed success.
Typically, the design of conventional deposition apparatuses and methods is dependent on desired resolution and spot size. Parameters that can be varied in designing such deposition apparatuses and methods can include the shape and size of the apparatus used for deposition, and the orientation of the apparatus with respect to the surface onto which material is to be deposited. In some cases, existing deposition apparatuses are energized (e.g., with an electromotive or electroosmotic force) to drive the deposition process. Such apparatuses are typically relatively complex and/or expensive. Also, in some cases (e.g., AFM probes), the deposition apparatus is shaped to include a protuberance at or near a tip of the apparatus to direct material toward a surface onto which the material is to be deposited. The protuberance can be oriented substantially orthogonally with respect to the surface or at a relatively steep angle with respect to the surface.